<!DOCTYPE html>
<html>
<head>

<style>
#outer { 
  -moz-column-count: 2;
}
#inner {
  border: 1px solid green;
}
</style>

<style id="s">
#inner { 
  float: right; 
  height: 1em; 
}
</style>

</head>

<body onload="document.getElementById('s').disabled = true;">

<div id="outer"><div id="inner"></div></div>

</body>
</html>
